code: def start_call(self, info):
      print("Starting new call:", info)
      return TracingClientMiddleware()
  
imports: import argparse
  import sys
  import threading
  import uuid
  import pyarrow
  import pyarrow.flight
label_desc: Use image node_id 1 for calling the TracingClientMiddlewareFactory obj's underlying member method code with example usage: obj.start_call(info) and returns: TracingClientMiddleware